High-precision mass and centroid measuring system and measuring method

Abstract

The invention relates to a high-precision mass and center-of-mass measurement system, which comprises a rotary support system, a measurement support system, a data acquisition system, a control system and a software analysis system, and is characterized in that the rotary support system comprises a left rotary support unit and a right rotary support unit which are symmetrically arranged and are used for supporting a to-be-measured workpiece and enabling the to-be-measured workpiece to rotate at a constant speed; the measurement supporting system comprises a left measurement supporting unit and a right measurement supporting unit and is used for measuring workpiece data, the data acquisition system acquires sensor data and inputs the sensor data to the control system and the software analysis system, after acquisition is completed, the workpiece is converted to be supported by the rotary supporting system, the angle is rotated, and after multiple times of measurement, the position of the center of mass is analyzed and calculated. The three-dimensional scanning technology is introduced into mass center measurement, a high-precision mass center measurement system is developed, and the measurement method has the advantages of being high in measurement precision, good in equipment universality and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of centroid measurement, and particularly to a high-precision mass centroid measurement system. Background Art

[0002] The measurement of mass characteristic parameters is a series of mechanical characteristic parameters related to mass, mainly including mass, centroid, moment of inertia, and product of inertia, etc. These parameters are all basic inherent characteristic parameters describing the mechanical characteristics of an object. Among them, the measurement of the centroid of an object is a key technology in the measurement of object mass characteristic parameters, providing important basic research data for scientific research and production. However, with the development and progress of science and technology, aircraft, missiles, rockets, ships, and curved workpieces are no longer limited to simple basic structures, with increasingly diverse shapes, more precise design requirements, and higher difficulty and precision in attitude control. This further requires improving the accuracy of centroid measurement in mass characteristic measurement.

[0003] The suspension method and the weighing method in the measurement of the centroid of an object are common methods in centroid measurement methods. During the process of measuring the centroid of an object by the traditional suspension method, it is difficult to collect the extension line of the suspension point, which brings difficulties to the subsequent centroid calculation and generates errors; the traditional weighing method and many improved measurement methods based on the weighing method have problems such as the need for initial leveling of the measurement table and precise conversion between the reference coordinate system and the product coordinate system. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art. Aiming at the problems that traditional centroid measurement requires manufacturing special fixtures, the test process is complex, the test cost is high, and the accuracy is low, this solution introduces three-dimensional scanning technology into centroid measurement to provide a high-precision mass centroid measurement system. This method has the advantages of high measurement accuracy and good equipment versatility.

[0005] The present invention solves its technical problems through the following technical solutions:

[0006] A high-precision mass and centroid measurement system, which includes a rotating support system, a measurement support system, a data acquisition system, a control system, and a software analysis system. The rotating support system includes symmetrically arranged left and right rotating support units, and the left and right rotating support units are used to support the workpiece to be measured and rotate it at a constant speed. The measurement support system includes left and right measurement support units, and the left and right measurement support units are each provided with a lifting unit, a sensor unit, and a measurement support block. The lifting unit slowly raises the sensor unit and the measurement support block as a whole, gradually contacts the workpiece until the entire mass of the workpiece is supported by the two measurement support blocks, and keeps it in a stable static state. The data acquisition system collects the data of the sensor unit and inputs it into the control system and the software analysis system. After the collection is completed, the measurement support system descends, transfers the workpiece to be supported by the rotating support system, rotates the angle, and then starts the measurement of the next position.

[0007] Moreover, the rotating support system includes left and right rotating support units, and the left and right rotating support units each include a first support bottom plate, a first wheel set, a bracket, a driving roller, and a driven roller. The bracket is fixedly installed on the upper part of the support bottom plate, and the driving roller and the driven roller are arranged at the top of the bracket. The first wheel set is arranged at the bottom of the first support bottom plate. The driving roller drives the workpiece to rotate by using the friction force between the driving roller and the workpiece under the drive of the driving motor, and the rotation angle is controlled by the control system.

[0008] Moreover, the measurement support system includes left and right measurement support units, and the left and right measurement support units are composed of a second support bottom plate, a second wheel set, a lifting unit, a guiding mechanism, a sensor unit, and a measurement support block. The second wheel set is arranged at the bottom of the second support bottom plate, the lifting unit and its guiding mechanism are arranged on the upper part of the second support plate, the measurement support block is arranged at the top of the lifting unit, and the sensor unit is arranged on the measurement support block. The sensor unit includes a first sensor unit arranged on the support block of the left measurement support unit and a second sensor unit arranged on the measurement support block of the right measurement support unit. The lifting unit drives the sensor unit and the measurement support block to move up and down, and the measurement support block is in line contact with the workpiece.

[0009] Moreover, the data acquisition system includes a large-scene laser scanner with a scanning range covering 50 - 80 meters and a scanning error less than 1 mm, which collects the point cloud data of the workpiece and the measurement support block.

[0010] A measurement method based on the high-precision mass and centroid measurement system includes the following steps:

[0011] Step 1: Adjust the measurement support system to the specified position and lock it to prevent it from moving due to lateral force. Lower the measurement support system to its reset position, hoist the workpiece to be measured onto the rotary support system, and rotate the workpiece to observe whether it is stable.

[0012] Step 2: After zeroing the first and second sensor units, the lifting units of the left and right measurement support units drive the measurement support blocks to rise. The measurement support blocks of the left and right measurement support units are lifted synchronously. After stabilization, record the data of the first and second sensor units. The data acquisition system includes a large-scene laser scanner for scanning to collect the data of the workpiece and the measurement support blocks to obtain point cloud data. After recording, the measurement support blocks of the left and right measurement support units synchronously descend, and the workpiece to be measured falls back to the rotary support system.

[0013] Step 3: Arrange the second pose of the workpiece to be measured, start the rotary support system, rotate the workpiece to be measured by an angle along its own rotation direction, and then repeat step 2), rotate the angle evenly, and measure multiple times.

[0014] Step 4: Post-process the scanned point cloud data, including the alignment of multiple scans of the workpiece to be measured, the setting of the product coordinate system, the fitting of the gravity direction, and the position coordinates of the contact points. After obtaining the data, analyze the centroid position; examine the stability of the data, eliminate gross errors, and give the results and print a report.

[0015] Moreover, the process of obtaining the data in step 4 is as follows: The support blocks are in a balanced state through the first sensor unit and the second sensor unit to determine the magnitude of the force at each support point; at the same time, scan the workpiece to be measured and the support positions to obtain the coordinate data of each support point, so as to analyze the gravity action line in this state. After measuring at multiple positions, obtain the gravity lines in multiple position states, and then based on the point cloud data, convert the gravity lines to a coordinate system to calculate the centroid coordinates.

[0016] Moreover, the specific process of step 4 is as follows:

[0017] 4.1 Collect the acting force at the support points:

[0018] Set the support point of the first support seat as point A, and the support point of the second support seat as point B. The acting force at point A is F A (i) , and the support acting force at point B is F B (i) ; The acting force at point A is F A (i) , and the support acting force at point B is F B (i) which are the average values of the force data measured by multiple load cells at point A and point B;

[0019] 4.2 Measure the center of gravity line in the i-th measurement state:

[0020] From the point cloud data, the coordinates of point A can be obtained as A (i) (x A (i) , y A (i) , z A (i) ), and the coordinates of point B are B (i) (x B (i) , y B (i) , z B (i) );

[0021] The projection point P of the center of gravity line of such a state on the XY plane (i) is (X P (i) , Y P (i) , ). According to the principle of moment balance, taking the moment about the X-axis, the equation can be obtained:

[0022] F A (i) *y A (i) +F B (i) *y B (i) -[(F A (i) +F B (i) )*Y P (i) = 0 (1)

[0023] Solving the equation, Y P (i)

[0024] Y P (i) =(F A (i) *y A (i) +F B (i) *y B (i) ) / (F A (i) +F B (i) ) (2)

[0025] Similarly, according to the principle of moment balance, taking the moment about the Y-axis, X P (i) is

[0026] X P (i) = (F A (i) * x A (i) + F B (i) * x B (i) ) / (F A (i) + F B (i) ) (3)

[0027] Since the Z - axis is parallel to the direction of gravity, draw a parallel line to the Z - axis through the projection point P (i) to obtain the center - of - gravity line L (i) , and this line is the center - of - gravity line in the i - th measurement state;

[0028] 4.3 Calculate the center - of - gravity coordinates:

[0029] After completing n (n≥2) state measurements, n center - of - gravity lines L (i) (i = 1, 2, …, n) can be obtained.

[0030] According to the product point - cloud model, the workpiece (1) under each measurement state can be transformed into a coordinate system;

[0031] Assume that the coordinate system of the theoretical model is C0, and the transformation matrix for converting the product scan point - cloud data at the i - th measurement to the theoretical model coordinate system C0 is J (i) , then L (i) transformed to the theoretical model coordinate system is

[0032] L c0 (i) = L (i)* J (i) (4)

[0033] The center - of - mass lines in each state can be transformed to the theoretical model coordinate system, obtaining n straight - line families:

[0034] Lp {L c0 (1) , L c0 (2) , …, L c0 (n)}; Assume that the center - of - gravity point is (Xc, Yc, Zc), and the distance from this point to the line L c0 (i) is D (i) , and using the least - squares method, find the optimal solution that satisfies the following constraints:

[0035] Err = min(∑(D (i) )^2) ((i = 1, 2, …, n)) (5)

[0036] The centroid coordinates (Xc, Yc, Zc) are obtained.

[0037] The beneficial effects of the present invention are as follows:

[0038] 1. For the problems of the traditional centroid measurement that special fixtures need to be manufactured, the test process is complex, the test cost is high, and the accuracy is low, the high-precision mass centroid measurement system and measurement method of the present invention introduce 3D scanning technology into centroid measurement and develop a high-precision centroid measurement system. The measurement method of the present invention has the advantages of high measurement accuracy and good equipment versatility.

[0039] 2. For the high-precision mass centroid measurement system and measurement method of the present invention, according to the principle of static moment balance and the equilibrium equation of static force system, the balance state of the object is supported by multiple sensors to determine the magnitude of the force at each support point; at the same time, the measured object and the support position are scanned to obtain the force and coordinate data at each support point, so as to analyze the line of action of gravity in this state. After multiple position measurements, multiple gravity lines in multiple position states can be obtained. Then, based on the point cloud data, the gravity lines are converted into a coordinate system to obtain the centroid coordinates.

[0040] 3. For the high-precision mass centroid measurement system and measurement method of the present invention, introducing a high-precision scanner into the measurement process can solve the problem of accurately determining the contact points between the measurement group and the measured part. During the measurement process, it is not necessary to level the measurement table, and the rotation angle of the measured part does not need to be accurately rotated.

[0041] 4. For the high-precision mass centroid measurement system and measurement method of the present invention, when the measurement starts, the lifting unit of the measurement support system slowly raises the sensor and the measurement support block as a whole, gradually contacts the workpiece until the entire mass of the workpiece is completely supported by the two measurement support blocks. It processes a stable static state, collects sensor data and subsequent data collection. After the collection is completed, the system descends, transfers the workpiece to be supported by the rotation support system, rotates the angle, and then starts the measurement of the next position; during the measurement, the measurement support block is in line contact with the workpiece. Through the data collection and acquisition system, the contact line in space can be obtained, providing accurate contact point coordinates for the calculation of the centroid line.

[0042] 5. The high-precision mass centroid measurement system and measurement method of the present invention involve large-sized parts. Using traditional methods, the influence of factors such as machining error, positioning error, and assembly error on the measurement accuracy is significant and difficult to control. The data acquisition system adopted by the present invention can obtain the actual position during actual measurement, providing a basis for high-precision centroid measurement. With the progress of scanning technology, the scanning accuracy, range, and efficiency have been extremely improved. Brief Description of the Drawings

[0043] Figure 1 It is a schematic structural diagram of the high-precision mass centroid measurement system of the present invention;

[0044] Figure 2 It is a schematic structural diagram of the rotary support system of the present invention;

[0045] Figure 3 It is a side view of the rotary support system of the present invention;

[0046] Figure 4 It is a schematic structural diagram of the measurement support system of the present invention;

[0047] Figure 5 It is a side view of the measurement support system of the present invention;

[0048] Figure 6 It is a schematic diagram of the test process of the present invention;

[0049] Figure 7 It is the scan data in a certain measurement state;

[0050] Figure 8 It is a schematic diagram of the contact point position between the analysis standard part and the measurement support block;

[0051] Figure 9 It is to find the optimal intersection point of the three centroid lines, which is the schematic diagram of the center point.

[0052] Explanation of the reference numerals in the drawings:

[0053] 1 - workpiece, 2 - left rotary support unit, 3 - left measurement support unit, 4 - control system and software analysis system, 5 - data acquisition system, 6 - right measurement support unit, 7 - right rotary support unit, 8 - driven roller, 9 - driving roller, 10 - driving motor, 11 - bracket, 12 - first support base plate, 13 - first wheel set, 14 - measurement support block, 15 - second support base plate, 16 - second wheel set, 17 - sensor unit, 18 - lifting unit, 19 - guiding mechanism. Detailed Embodiment

[0054] The present invention will be further described in detail below through specific embodiments. The following embodiments are only descriptive and not restrictive, and the protection scope of the present invention cannot be limited thereby.

[0055] A high-precision mass and centroid measurement system, which includes a rotary support system, a measurement support system, a data acquisition system 5, a control system, and a software analysis system 4. The rotary support system includes symmetrically arranged left rotary support units 2 and right rotary support units 7. The left rotary support unit and the right rotary support unit are used to support the workpiece to be measured and make it rotate at a constant speed. The measurement support system includes a left measurement support unit 3 and a right measurement support unit 6. The left measurement support unit and the right measurement support unit are both provided with a lifting unit 18, a sensor unit 17, and a measurement support block 14. The lifting unit slowly raises the sensor unit and the measurement support block as a whole, gradually contacting the workpiece until the entire mass of the workpiece 1 is supported by the two measurement support blocks, making it in a stable static state. The data acquisition system collects sensor data and inputs it into the control system and the software analysis system. After the acquisition is completed, the measurement support system descends, transfers the workpiece to be supported by the rotary support system, rotates by an angle, and then starts the measurement of the next position.

[0056] The left rotary support unit and the right rotary support unit of the rotary support system both include a first support bottom plate 12, a first wheel set 13, a bracket 11, a driving roller 9, and a driven roller 8. The driving roller 9 is driven by its driving motor 10. A bracket is fixedly installed on the upper part of the first support bottom plate. The bracket forms a concave arc shape. A driving roller and a driven roller are respectively arranged at the tops on both sides of the concave arc of the bracket. A first wheel set is arranged at the bottom of the first support bottom plate. The driving roller drives the workpiece to rotate by using the friction force between the driving roller and the workpiece under the drive of the driving motor. The rotation angle is controlled by the control system and disengages from the workpiece during the mass and centroid measurement.

[0057] The measurement support system includes a left measurement support unit and a right measurement support unit. The left measurement support unit and the right measurement support unit are composed of a second support bottom plate 15, a second wheel set 16, a lifting unit 18, a guiding mechanism 19, a sensor unit 17, and a measurement support block 14. A second wheel set is arranged at the bottom of the second support bottom plate. A lifting unit and its guiding mechanism are arranged on the upper part of the second support plate. A support block is arranged at the top of the lifting unit, and a sensor unit is arranged on the support block. The sensor unit includes a first sensor unit and a second sensor unit arranged on the support blocks of the left measurement support unit and the right measurement support unit. Both the first sensor unit and the second sensor unit include at least two weighing sensors. The lifting unit drives the sensor and the support block to move up and down. The measurement support block is arc-shaped and thin plate-shaped, and the measurement support block is in line contact with the workpiece.

[0058] When the measurement starts, the lifting unit of the measurement support system slowly raises the sensor unit and the measurement support block as a whole, gradually contacts the workpiece until the mass of the entire workpiece is completely supported by the two measurement support blocks. Let it be in a stable static state, collect the data of the sensor unit and perform subsequent data collection. After the collection is completed, the system descends, transfers the workpiece to be supported by the rotary support system, rotates the angle, and then starts the measurement of the next position. During the measurement, the measurement support block is in line contact with the workpiece. Through the data collection system, the contact line in space can be obtained, providing accurate contact point coordinates for the calculation of the centroid line.

[0059] The data collection system includes a large-scene laser scanner with a scanning range covering 50 - 80 meters and a scanning error less than 1 mm, which collects data of the workpiece and the measurement support block. The laser scanning device has the advantages of fast speed, high precision, and small volume, and can conveniently adjust the position of the scanning device according to needs to collect the data of the workpiece and the measurement support block.

[0060] The function of the control system is to control the positions of the rotary support system and the measurement support system, control the rotation of the workpiece, control the lifting of the measurement support system, and collect the data of the sensor unit. The function of the software system is to unify the coordinate systems of the centroid lines of multiple measurements and obtain the optimal centroid coordinates.

[0061] A measurement method based on a high-precision mass centroid measurement system, which includes the following steps:

[0062] Step 1: Adjust the measurement support system to the specified position and lock it. The lifting unit is hydraulically driven and locked by hydraulic control to prevent it from moving due to lateral force. The measurement support system descends and resets, hoist the workpiece to be measured onto the rotary support system, rotate the workpiece, and observe whether it is stable;

[0063] Step 2: After the first and second sensor units are zeroed, the lifting units of the left measurement support unit and the right measurement support unit drive the support blocks to rise. The support blocks of the left measurement support unit and the right measurement support unit are lifted synchronously. After stabilization, record the data of the first sensor unit and the second sensor unit. The data collection system includes a large-scene laser scanner for scanning to collect the data of the workpiece and the measurement support block to obtain point cloud data. After recording, the support blocks of the left measurement support unit and the right measurement support unit descend synchronously, and the workpiece to be measured falls back to the rotary support system;

[0064] Step 3: Place the workpiece to be measured in the second pose, start the rotary support system, rotate the workpiece to be measured by an angle along its own rotation direction, and then repeat step 2), rotate the angle evenly, and perform multiple measurements;

[0065] Step 4. Post-process the scanned workpiece and the point cloud data of the measurement support block, including alignment of multiple scans of the workpiece to be measured, setting of the product coordinate system, fitting of the gravity direction, and contact point position coordinates. After obtaining the data, analyze the centroid position; examine the stability of the data, eliminate gross errors, and give the results and print a report.

[0066] The process of obtaining the data in Step 4 is as follows: Determine the magnitude of the force at each support point by balancing the object at multiple load cells; simultaneously scan the object to be measured and the support positions to obtain the coordinate data of each support point, thereby analyzing the gravity action line in this state. After measuring at multiple positions, multiple gravity lines in different positions can be obtained. Then, based on the point cloud data, convert the gravity lines to a coordinate system to obtain the centroid coordinates.

[0067] The specific process of Step 4 is as follows:

[0068] During measurement, scans need to be performed in multiple states to obtain the point cloud data of the workpiece to be measured and the support block in each state. Assume that during the i-th state measurement, the point cloud data of the workpiece to be measured and the support block are scanned. Use the calculation function of GeomagicStudio software to adjust the coordinate system of the point cloud data after multiple state measurements, so that the z-axis of the coordinate system of the point cloud data after multiple state measurements is parallel to the gravity direction, realizing automatic alignment of the point cloud.

[0069] As Figure 6 shown, set the support point of the first support seat as point A and the support point of the second support seat as point B. Then the force at point A is F A (i) , and the support force at point B is F B (i) ; Through the point cloud data, the coordinates of point A can be obtained as A (i) (x A (i) , y A (i) , z A (i) ), and the coordinates of point B are B (i) (x B (i) , y B (i) , z B (i) ).

[0070] The force at point A is F A (i) , and the support force at point B is F B (i) which are the average values of the force data measured by multiple load cells at point A and point B.

[0071] The projection point P of the center-of-gravity line of this state on the XY plane (i) is (X P (i) , Y P (i) ). According to the principle of moment balance, taking the moment about the X-axis, the equation can be obtained as follows:

[0072] F A (i) *y A (i) +F B (i) *y B (i) -[(F A (i) +F B (i) )*Y P (i) = 0 (1)

[0073] Solving the equation, Y P (i)

[0074] Y P (i) =(F A (i) *y A (i) +F B (i) *y B (i) ) / (F A (i) +F B (i) ) (2)

[0075] Similarly, according to the principle of moment balance, taking the moment about the Y-axis, X P (i) is

[0076] X P (i) =(F A (i) *x A (i) +F B (i) *x B (i) ) / (F A (i) +F B (i) ) (3)

[0077] Since the Z-axis is parallel to the direction of gravity, passing through the projection point P (i)By drawing a line parallel to the Z-axis, the centroid line L can be obtained. (i) This line is the centroid line in the i-th measurement state.

[0078] After completing n (n≥2) state measurements, n centroid lines L (i) (i = 1, 2,..., n) can be obtained.

[0079] According to the product point cloud model, the measured workpiece models in each measurement state can be transformed into a coordinate system.

[0080] Assume that the coordinate system of the theoretical model is C0, and the transformation matrix for converting the product scan point cloud data at the i-th measurement to the theoretical model coordinate system C0 is J (i) , then L (i) transformed to the theoretical model coordinate system is

[0081] L c0 (i) = L (i)* J (i) (4)

[0082] Then the centroid lines in each state can be transformed to the theoretical model coordinate system, obtaining n straight line families:

[0083] Lp{L c0 (1) , L c0 (2) , …, L c0 (n)}; Assume that the centroid point is (Xc, Yc, Zc), and the distance from this point to the line L c0 (i) is D (i) . Using the least squares method, find the optimal solution that satisfies the following constraint conditions:

[0084] Err = min(∑(D (i) )^2) ((i = 1, 2,..., n)) (5)

[0085] Find the centroid coordinates as (Xc, Yc, Zc).

[0086] The working parameters of the laser scanner in the measurement system of the present invention are:

[0087] Voltage: AC220V; Frequency: 50Hz; Scanning range: <80m; Single-frame scanning accuracy: ≤0.05mm;

[0088] Measurement range: Length not greater than 60m; Measured cylinder diameter: <5m; Measurement error: ±2.5mm.

[0089] Specific calculation example:

[0090] As shown Figure 7 in the scanning data under a certain measurement state; Figure 8 As shown, analyze the contact point position between the analysis standard part and the measurement support block, and simply calculate the centroid projection point for each time, as shown in the following table:

[0091] Table 1

[0092]

[0093] As shown Figure 9 in the figure, after multiple measurements, calculate the centroid line for each measurement, align the data through point cloud data, and convert it to the same coordinate system. Conduct three measurements to obtain three straight lines. Find the optimal intersection point of the three straight lines, which is the center point. The analysis of errors is shown in Table 2. The measurement method of the present invention has high measurement accuracy.

[0094] Table 2

[0095] Barycentric coordinates Measured value Theoretical value Error XC 51.4 51.36 0.04 YC 40.56 40.47 0.09 ZC 41.2 41.12 0.08

[0096] Compared with the traditional method, the measurement method of the present invention has significant advantages, which are mainly manifested in the following aspects:

[0097] (1) It can achieve high-precision centroid measurement of the workpiece to be measured;

[0098] (2) The shape and material of the object do not affect the measurement accuracy, and it can be measured efficiently without an accurate reference plane;

[0099] (3) The measurement platform has strong versatility;

[0100] (4) The measurement process does not require an auxiliary positioning device.

[0101] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art can understand that various substitutions, changes, and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the content disclosed in the embodiments and drawings.

Claims

1. A high-precision mass and centroid measurement system, characterized in that: It includes a rotary support system, a measurement support system, a data acquisition system (5), a control system and a software analysis system (4). The rotary support system includes a left rotary support unit (2) and a right rotary support unit (7) which are symmetrically arranged. The left rotary support unit (2) and the right rotary support unit (7) are used to support the workpiece to be measured (1) and make it rotate at a constant speed. The measurement support system includes a left measurement support unit (3) and a right measurement support unit (6). The left measurement support unit (3) and the right measurement support unit (6) are both provided with a lifting unit (18), a sensor unit (17), and a measurement support block (14). The lifting unit (18) slowly raises the sensor unit (14) and the measurement support block (14) as a whole, gradually contacting the workpiece (1) until the mass of the entire workpiece (1) is completely supported by the two measurement support blocks (14), making it in a stable static state. The data acquisition system (5) collects the data of the sensor unit (17) and inputs it into the control system and the software analysis system (4). After the collection is completed, the measurement support system descends, transfers the workpiece (1) to be supported by the rotary support system, rotates by an angle, and then starts the measurement of the next position.

2. The high-precision mass centroid measurement system according to claim 1, wherein: The rotary support system includes a left rotary support unit (2) and a right rotary support unit (7). The left rotary support unit (2) and the right rotary support unit (7) both include a first support bottom plate (12), a first wheel set (13), a bracket (11), a driving roller (9) and a driven roller (8). The bracket (11) is fixedly installed on the upper part of the support bottom plate. The driving roller (9) and the driven roller (8) are arranged at the top of the bracket (11). The first wheel set (13) is arranged at the bottom of the first support bottom plate (12). Driven by the driving motor (10), the driving roller (9) drives the workpiece (1) to rotate by using the friction force between the driving roller (9) and the workpiece (1). The rotation angle is controlled by the control system.

3. The high-precision mass and centroid measurement system according to claim 1, wherein: The measurement support system includes a left measurement support unit (3) and a right measurement support unit (6). The left measurement support unit (3) and the right measurement support unit (6) are composed of a second support bottom plate (15), a second wheel set (16), a lifting unit (18), a guiding mechanism (19), a sensor unit (17) and a measurement support block (14). The second wheel set (16) is arranged at the bottom of the second support bottom plate (15). The lifting unit (18) and its guiding mechanism (19) are arranged on the upper part of the second support plate. The measurement support block (14) is arranged at the top of the lifting unit (18). The sensor unit (17) is arranged on the measurement support block (14). The sensor unit (17) includes a first sensor unit arranged on the support block (14) of the left measurement support unit (3) and a second sensor unit arranged on the measurement support block (14) of the right measurement support unit (6). The lifting unit (18) drives the sensor unit and the measurement support block (14) to move up and down, and the measurement support block (14) is in line contact with the workpiece (1).

4. The high-precision mass centroid measurement system according to claim 1, wherein: The data acquisition system (5) includes a large-scene laser scanner with a scanning range covering 50 - 80 meters and a scanning error less than 1 mm, which acquires the point cloud data of the workpiece (1) and the measuring support block (14).

5. A measurement method based on a high-precision mass centroid measurement system, characterized in that: It includes the following steps: Step 1: Adjust the measuring support system to the specified position and lock it to prevent it from moving due to lateral force. The measuring support system descends and resets. Lift the workpiece (1) to be measured onto the rotating support system and rotate the workpiece (1) to observe whether it is stable; Step 2: After the first and second sensor units are cleared, the lifting units (18) of the left measuring support unit (3) and the right measuring support unit (6) drive the measuring support blocks (14) to rise. The measuring support blocks (14) of the left measuring support unit (3) and the right measuring support unit (6) are lifted synchronously. After stabilization, record the data of the first and second sensor units. The data acquisition system (5) includes a large-scene laser scanner for scanning to acquire the data of the workpiece (1) and the measuring support block (14) to obtain point cloud data. After recording, the measuring support blocks (14) of the left measuring support unit (3) and the right measuring support unit (6) descend synchronously, and the workpiece (1) to be measured falls back to the rotating support system; Step 3: Place the workpiece (1) to be measured in the second pose, start the rotating support system, rotate the workpiece to be measured by an angle along its own rotation direction, and then repeat Step 2), rotate the angle evenly, and measure multiple times; Step 4: Post-process the scanned point cloud data, including alignment of multiple scans of the workpiece to be measured, setting of the product coordinate system, fitting of the gravity direction, and contact point position coordinates. After obtaining the data, analyze the centroid position; examine the stability of the data, eliminate gross errors, and give the results and print a report.

6. The high-precision mass centroid measurement method according to claim 1, wherein: The process of obtaining the data in Step 4 is as follows: When the support blocks are in a balanced state through the first sensor unit and the second sensor unit, the magnitude of the force at each support point is determined; at the same time, scan the workpiece to be measured and the support positions to obtain the coordinate data of each support point, so as to analyze the gravity action line in this state. After measuring at multiple positions, obtain the gravity lines in multiple position states, and then based on the point cloud data, convert the gravity lines to a coordinate system and calculate the centroid coordinates.

7. The high-precision mass and centroid measurement method according to claim 1, characterized in that: The specific process of Step 4 is as follows: 4.1 Collect the acting force at the support point: Set the support point of the first support base as point A and the support point of the second support base as point B. The acting force at point A is F A (i) , and the supporting force at point B is F B (i) ; The acting force at point A is F A (i) , and the supporting force at point B is F B (i) is the average value of the force data measured by multiple weighing sensors at point A and point B; 4.2 Measure the gravity line in the i-th measurement state: Through the point cloud data, the coordinates of point A can be obtained as A (i) (x A (i) , y A (i) , z A (i) ), and the coordinates of point B are B (i) (x B (i) , y B (i) , z B (i) ); The projection point P of the center of gravity line of such a state on the XY plane (i) is (X P (i) , Y P (i) , ). According to the principle of moment balance, taking the moment about the X-axis, the equation can be obtained as follows: F A (i) *y A (i) +F B (i) *y B (i) -[(F A (i) +F B (i) )*Y P (i) =0 (1) Solving the equation, Y can be obtained P (i) Y P (i) =(F A (i) *y A (i) +F B (i) *y B (i) ) / (F A (i) +F B (i) ) (2) Similarly, according to the principle of moment balance, taking the moment about the Y-axis, X can be obtained P (i) be X P (i) =(F A (i) *x A (i) +F B (i) *x B (i) ) / (F A (i) +F B (i) ) (3) Since the Z-axis is parallel to the direction of gravity, passing through the projection point P (i) draw a parallel line to the Z-axis, and the center of gravity line L can be obtained (i) , and this straight line is the center of gravity line in the i-th measurement state; 4.3 Calculate the centroid coordinates: After completing n (n≥2) state measurements, n center lines L can be obtained. (i) (i = 1, 2,..., n). According to the product point cloud model, the workpiece (1) to be measured in each measurement state can be converted to a coordinate system; Assume that the coordinate system of the theoretical model is C0, and the transformation matrix for converting the scanned point cloud data of the product to the theoretical model coordinate system C0 during the i-th measurement is J (i) , then L (i) Converted to the theoretical model coordinate system is L c0 (i) = L (i)* J (i) (4) The centroid lines in each state can be converted to the theoretical model coordinate system to obtain n straight line families: Lp{L c0 (1) ,L c0 (2) ,…,L c0 (n)}; Assume the centroid is (Xc, Yc, Zc), and the distance from this point to the line L c0 (i) is D (i) , and use the least squares method to find the optimal solution that satisfies the following constraint conditions: Err = min(∑(D (i) )^2) ((i = 1, 2, …, n)) (5) Calculate the centroid coordinates as (Xc, Yc, Zc).

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